Effectiveness of acute normovolemic hemodilution to minimize allogeneic blood transfusion in major liver resections

Tranexamic Acid in Patients Undergoing Liver Resection: An Updated Systematic Review and Meta-Analysis of Randomized Controlled Trials

BackgroundTranexamic acid (TA), a synthetic lysine derivative, is known for its antifibrinolytic effect and potential to reduce bleeding in surgeries like arthroplasty, cardio-aortic procedures, and liver transplantation. This meta-analysis seeks to provide robust clinical evidence on TA's effectiveness in reducing blood loss and transfusion needs during orthotopic liver transplantation.MethodsThe systematic review and meta-analysis included the relevant randomized controlled trials (RCTs) retrieved from PubMed, EMBASE, Web of Science, Cochrane, and SCOPUS databases until August 2024. The meta-analysis was done using (RevMan 5.4.1). PROSPERO ID: CRD42024589151.ResultsOur meta-analysis of seven RCTs with 1875 patients found no significant differences between TA and control groups in total red blood cell units transfused (MD: -3.74 units; 95% CI [-8.49, 1.01]; P = .12), perioperative transfusions (MD: -0.42 units; 95% CI [-3.17, 2.32]; P = .76), or overall blood loss (MD: -167.81 mL; 95% CI [-415.29, 79.67]; P = .18).For safety outcomes, TA was associated with a higher rate of venous thromboembolism events (RR: 1.71; 95% CI [1.01, 2.87]; P = .05; event rate: 4.89% vs 2.91%), while no significant differences were found in other surgical complications (RR: 1.12; 95% CI [0.92, 1.37]; P = .26).ConclusionTA does not reduce blood loss or the need for postoperative transfusions in orthotopic liver transplantation and may raise thrombotic risk. Caution is required to interpret these results due to variations in the study/hospital-specific transfusion protocol details. Larger studies are needed to confirm these findings, and future research should explore the effects of multiple dosing regimens on blood loss and transfusion requirements.

Effects of acute normovolemic hemodilution and allogeneic blood transfusion on postoperative complications of oral and maxillofacial flap reconstruction: a retrospective study

OBJECTIVE

Patients undergoing oral and maxillofacial flap reconstruction often need blood transfusions due to massive blood loss. With the increasing limitations of allogeneic blood transfusion (ABT), doctors are considering acute normovolemic hemodilution (ANH) because of its advantages. By comparing the differences in the (Δ) blood indices and postoperative complications of patients receiving ABT or ANH during the reconstruction and repair of oral and maxillofacial tumor flaps, this study's purpose was to provide a reference for the clinical application of ANH.

METHODS

The clinical data of 276 patients who underwent oral and maxillofacial flap reconstruction from September 25, 2017, to October 11, 2021, in the Department of Oral and Maxillofacial Surgery, Sun Yat-sen Memorial Hospital, were retrospectively analyzed. According to the intraoperative blood transfusion mode, the patients were divided into two groups: ABT and ANH. The differences in the (Δ) blood indices and the incidence of postoperative complications between the groups were analyzed.

RESULTS

Among the 276 patients who had ANH (124/276) and ABT (152/276), there were no differences in (Δ) Hb, (Δ) PT, or (Δ) FIB (P > 0.05), while (Δ) WBC, (Δ) PLT, (Δ) APTT and (Δ) D-dimer were significantly different (P < 0.05). The blood transfusion method was not an independent factor for flap crisis (P > 0.05). The wound infection probability in patients with high post-PTs was 1.953 times greater than that in patients with low post-PTs (OR = 1.953, 95% CI: 1.232 ∼ 3.095, P = 0.004). A normal or overweight BMI was a protective factor for pulmonary infection, and the incidence of pulmonary infection in these patients was only 0.089 times that of patients with a low BMI (OR = 0.089, 95% CI: 0.017 ∼ 0.462). Moreover, a high ASA grade promoted the occurrence of pulmonary infection (OR = 6.373, 95% CI: 1.681 ∼ 24.163). The blood transfusion mode (B = 0.310, β = 0.360, P < 0.001; ANH: ln hospital stay = 2.20 ± 0.37; ABT: ln hospital stay = 2.54 ± 0.42) improved the length of hospital stay.

CONCLUSION

Preoperative and postoperative blood transfusion (Δ) Hb, (Δ) PT, and (Δ) FIB did not differ; (Δ) WBC, (Δ) PLT, (Δ) APTT, and (Δ) D-dimer did differ. There was no difference in the effects of the two blood transfusion methods on flap crisis, incision infection or lung infection after flap reconstruction, but ANH resulted in a 3.65 day shorter average hospital stay than did ABT.

Safe and Effective Blood Preservation Through Acute Normovolemic Hemodilution and Low-Dose Tranexamic Acid in Open Partial Hepatectomy

Objective

In this study, we evaluated the efficacy of tranexamic acid (TXA) and acute normovolemic hemodilution (ANH) with 6% hydroxyethyl starch (130/0.4) in minimizing blood loss during open partial liver resection. Coagulation function was assessed using thromboelastography (TEG) and hemostasis tests, while renal function changes were tracked through serum creatinine values post-surgery.

Methods

Thirty patients undergoing open partial liver resection were allocated to two groups: Group T received TXA + ANH, and Group A received ANH alone. Blood was drawn from the radial artery under general anesthesia. Both groups received peripheral vein injections of 6% hydroxyethyl starch 130/0.4. Group T additionally received intravenous TXA. Primary outcomes included blood loss and allogeneic blood transfusions. TEG assessed coagulation status and renal function was monitored.

Results

Group T demonstrated superior outcomes compared to Group A. Group T had significantly lower intraoperative blood loss (700 mL vs 1200 mL) and a lower bleeding rate per kilogram of body weight (13.3 mL/kg vs 20.4 mL/kg). Coagulation parameters favored Group T, with higher TEG maximum amplitude (55.91 mm vs 45.88 mm) and lower activated partial thromboplastin time (38.04 seconds vs 41.49 seconds). Neither group experienced acute renal injury or kidney function deficiency during hospitalization.

Conclusion

TXA and ANH in a small dose during liver resection stabilize clotting, reduce blood loss by 6% compared to hydroxyethyl starch 130/0.4, and do not affect renal function.

Application of cardiovascular interventions to decrease blood loss during hepatectomy: a systematic review and meta-analysis

BACKGROUND

Perioperative bleeding and allogeneic blood transfusion are generally thought to affect the outcomes of patients. This meta-analysis aimed to determine the benefits and risks of several cardiovascular interventions in patients undergoing hepatectomy.

METHODS

In this systematic review and meta-analysis, randomised controlled trials (RCTs) were searched in the Cochrane Library, Medline, Embase, and Web of Science to February 02, 2023. RCTs focused on cardiovascular interventions aimed at reducing blood loss or blood transfusion requirements during hepatectomy were included. The primary outcomes were perioperative blood loss amount, number of patients requiring allogeneic blood transfusion and overall occurrence of postoperative complications. The secondary outcomes were operating time, perioperative mortality rate, postoperative liver and kidney function and length of hospital stay.

RESULTS

Seventeen RCTs were included in the analysis. A total of 841 patients who underwent hepatectomy in 10 trials were included in the comparative analysis between low central venous pressure (CVP) and control groups. The forest plots showed a low operative bleeding volume [(mean difference (MD): -409.75 mL, 95% confidence intervals (CI) -616.56 to -202.94, P < 0.001], reduced blood transfusion rate [risk ratio (RR): 0.47, 95% CI 0.34 to 0.65, P < 0.001], shortened operating time (MD: -13.42 min, 95% CI -22.59 to -4.26, P = 0.004), and fewer postoperative complications (RR: 0.76, 95% CI 0.58 to 0.99, P = 0.04) in the low CVP group than in the control group. Five and two trials compared the following interventions, respectively: 'acute normovolaemic haemodilution (ANH) vs control' and 'autologous blood donation vs control'. ANH and autologous blood donation could not reduce the blood loss amount but greatly decreased the number of patients requiring allogeneic blood transfusion. No benefits were found in the rate of mortality and length of postoperative hospital stay in any of the comparisons.

CONCLUSION

Lowering the CVP seems to be effective and safe in adult patients undergoing hepatectomy. ANH and autologous blood donation should be used as a part of blood management for suitable patients in certain circumstances.

TRIAL REGISTRATION

PROSPERO, CRD42022314061.

Bloodless surgery in urologic oncology: A review of hematologic, anesthetic, and surgical considerations

The urologic oncology patient who refuses blood transfusion can present unique challenges in perioperative blood management. Since blood loss and associated transfusion can be expected in many complex urologic oncology surgeries, a multidisciplinary approach may be required for optimal outcomes. Through collaboration with the hematologist, anesthesiologist, and urologist, various techniques can be employed in the perioperative phases to minimize blood loss and the need for transfusion. We review the risks and benefits of these techniques and offer recommendations specific to the urologic oncology patient.

Acute Hemodilution is Safe in Patients with Comorbid Illness Undergoing Partial Hepatectomy

Despite increased use of acute hemodilution (AH) to reduce perioperative blood transfusion in patients undergoing partial hepatectomy, there is a lack of data on safety in those with comorbid medical illness. We performed a retrospective review of 96 patients undergoing partial hepatectomy with AH and low central venous pressure (CVP) anesthesia. The cohort was compared with 63 patients undergoing partial hepatectomy using standard anesthetic management (SA) and low CVP anesthesia. All were American Society of Anesthesiologists physical status 3 or 4. 58 per cent were baseline hypertensive on medication. Hepatic resection was predominantly performed for metastatic colorectal (41%) and primary hepatic (32%) cancer. Forty per cent underwent major hepatectomy. The mean volume of blood removed for AH was 497 mL (range, 0 to 1 L). Most achieved low CVP (AH 90% vs SA 84%, P = 0.3). Blood loss was lower with AH (mean 480 mL vs 904 mL, P < 0.001). Blood transfusion rate was 74 per cent lower with AH ( P < 0.001). There was no difference in cardiac, respiratory, renal, or overall complications with AH compared with SA. Acute hemodilution is well tolerated by patients with comorbid illness undergoing partial hepatectomy, favoring ongoing use and further study.

Acute normovolemic hemodilution reduced allogeneic blood transfusion without increasing perioperative complications in patients undergoing free-flap reconstruction of the head and neck

Purpose

The present case–control study was conducted to evaluate whether acute normovolemic hemodilution (ANH) can reduce the need for perioperative allogeneic blood transfusion (ABT) and affect the incidence of perioperative complications in free-flap reconstruction of the head and neck.

Methods

This single-center, retrospective, observational study included the perioperative data of 123 patients who underwent free-flap reconstruction of the head and neck following oncological surgery. Patients were divided into the following two groups according to whether they received ANH: ANH group and non-ANH group. We investigated whether ANH can reduce the need for perioperative ABT using propensity score-adjusted logistic regression analysis.

Results

Of the 123 patients, 113 patients were assessed; 57 patients were in the ANH group and 56 patients were in the non-ANH group. The rate [ANH group vs. non-ANH group, n (%): 2 (3.5%) vs. 23 (41.1%), p < 0.0001] and amount [median (IQR): 0 mL (0, 0) vs. 0 mL (0, 280), p < 0.0001] of ABT were significantly lower in the ANH group than in the non-ANH group. Propensity score-adjusted multivariate logistic regression analysis indicated that ANH use [odds ratio (OR): 0.040; 95% confidence interval (CI) 0.005, 0.320; p = 0.0024)] was one of the independent predictors of perioperative ABT. There were no significant differences in the incidences of post-operative complications between the two groups.

Conclusion

ANH use can reduce the need for perioperative ABT in patients undergoing free-flap reconstruction of the head and neck without increasing the incidence of post-operative complications.

Hypovolemic phlebotomy in liver surgery is associated with decreased red blood cell transfusion

BACKGROUND

Perioperative red blood cell (RBC) transfusion is associated with poor outcomes in liver surgery. Hypovolemic phlebotomy (HP) is a novel intervention hypothesized to decrease transfusion requirements. The objective of this study was to examine this hypothesis.

METHODS

Consecutive patients who underwent liver resection at one institution (2010-2016) were included. Factors found to be predictive of transfusion on univariate analysis and those previously published were modeled using multivariate logistic regression.

RESULTS

A total of 361 patients underwent liver resection (50% major). HP was performed in 45 patients. Phlebotomized patients had a greater proportion of primary malignancy (31% vs 18%) and major resection (84% vs 45%). Blood loss was significantly lower with phlebotomy in major resections (400 vs 700 mL). Nadir central venous pressure was significantly lower with HP (2.5 vs 5 cm H₂O). On multivariate logistic regression, HP (OR 0.20, 95% CI 0.068-0.57, p = 0.0029), major liver resection (OR 2.91, 95% CI 1.64-5.18, p = 0.0003), preoperative hemoglobin < 125 g/L (OR 6.02, 95% CI 3.44-10.56, p < 0.0001), and underlying liver disease (OR 2.24, 95% CI 1.27-3.95, p = 0.0051) were significantly associated with perioperative RBC transfusion.

CONCLUSION

Hypovolemic phlebotomy appears to be strongly associated with a reduction in RBC transfusion requirements in liver resection, independent of other known risk factors.

Short-term Preoperative Diet Decreases Bleeding After Partial Hepatectomy: Results From a Multi-institutional Randomized Controlled Trial

BACKGROUND

Our previous case series suggested that a 1-week, low-calorie and low-fat diet was associated with decreased intraoperative blood loss in patients undergoing liver surgery.

OBJECTIVE

The current study evaluates the effect of this diet in a randomized controlled trial.

METHODS

We randomly assigned 60 patients with a body mass index ≥25 kg/m(2) to no special diet or an 800-kcal, 20 g fat, and 70 g protein diet for 1 week before liver resection. Surgeons were blinded to diet assignment. Hepatic glycogen stores were evaluated using periodic acid Schiff (PAS) stains.

RESULTS

Ninety four percent of the patients complied with the diet. The diet group consumed fewer daily total calories (807 vs 1968 kcal, P < 0.001) and fat (21 vs 86 g, P < 0.001) than the no diet group. Intraoperative blood loss was less in the diet group: mean blood loss 452 vs 863 mL (P = 0.021). There was a trend towards decreased transfusion in the diet group (138 vs 322 mL, P = 0.06). The surgeon judged the liver to be easier to manipulate in the diet group: 1.86 versus 2.90, P = 0.004. Complication rate (20% vs 17%), length of stay (median 5 vs 4 days) and mortality did not differ between groups. There was no difference in hepatic steatosis between groups. There was less glycogen in hepatocytes in the diet group (PAS stain score 1.61 vs 2.46, P < 0.0001).

CONCLUSIONS

A short-course, low-fat, and low-calorie diet significantly decreases bleeding and makes the liver easier to manipulate in hepatic surgery.

Korean clinical practice guideline for perioperative red blood cell transfusion from Korean Society of Anesthesiologists

Background

Considering the functional role of red blood cells (RBC) in maintaining oxygen supply to tissues, RBC transfusion can be a life-saving intervention in situations of severe bleeding or anemia. RBC transfusion is often inevitable to address intraoperative massive bleeding; it is a key component in safe perioperative patient management. Unlike general medical resources, packed RBCs (pRBCs) have limited availability because their supply relies entirely on voluntary donations. Additionally, excessive utilization of pRBCs may aggravate prognosis or increase the risk of developing infectious diseases. Appropriate perioperative RBC transfusion is, therefore, crucial for the management of patient safety and medical resource conservation. These concerns motivated us to develop the present clinical practice guideline for evidence-based efficient and safe perioperative RBC transfusion management considering the current clinical landscape.

Methods

This guideline was obtained after the revision and refinement of exemplary clinical practice guidelines developed in advanced countries. This was followed by rigorous evidence-based reassessment considering the healthcare environment of the country.

Results

This guideline covers all important aspects of perioperative RBC transfusion, such as preoperative anemia management, appropriate RBC storage period, and leukoreduction (removal of white blood cells using filters), reversal of perioperative bleeding tendency, strategies for perioperative RBC transfusion, appropriate blood management protocols, efforts to reduce blood transfusion requirements, and patient monitoring during a perioperative transfusion.

Conclusions

This guideline will aid decisions related to RBC transfusion in healthcare settings and minimize patient risk associated with unnecessary pRBC transfusion.

Improvements in blood transfusion management: cross-sectional data analysis from nine hospitals in Zhejiang, China

BACKGROUND

Since 2008, updated perioperative blood management (PoBM) guidelines have been implemented in Zhejiang, China. These guidelines ensure that the limited blood resources meet increasing clinical needs and patient safety requirements. We assessed the effects of implementing updated PoBM guidelines in hospitals in Zhejiang, China.

METHODS

We performed a retrospective multicenter study that included adult patients who received blood transfusions during surgical care in the years 2007 and 2011. The volume of allogeneic red blood cells or autologous blood transfusions (cell salvage and acute normovolemic hemodilution [ANH]) for each case was recorded. The rates of performing appropriate pre-transfusion assessments during and after surgery were calculated and compared between the 2 years.

RESULTS

We reviewed 270,421 cases from nine hospitals. A total of 15,739 patients received blood transfusions during the perioperative period. The rates of intraoperative allogeneic transfusion (74.8% vs. 49.9%, p <  0.001) and postoperative transfusion (51.9% vs. 44.2%, p <  0.001) both decreased from 2007 to 2011; the rates of appropriate assessment increased significantly during (63.0% vs. 78.0%, p <  0.001) and after surgery (70.6% vs. 78.4%, p <  0.001). The number of patients who received cell salvage or ANH was higher in 2011 (27.6% cell salvage; 9.3% ANH) than in 2007 (6.3% cell salvage; 0.1% ANH).

CONCLUSION

Continuing education and implementation of updated PoBM guidelines resulted in significant improvements in the quality of blood transfusion management in hospitals in Zhejiang, China.

Three point transfusion risk score in hepatectomy: an external validation using the American College of Surgeons - National Surgical Quality Improvement Program (ACS-NSQIP)

BACKGROUND

Risk of red blood cell transfusion (RBCT) in partial hepatectomy is 17-27%; strategies to reduce transfusions can be targeted in patients at increased risk. A Three Point Transfusion Risk Score (TRS) was previously developed to predict patients' risk of transfusion during and following hepatectomy. Here, it was subject to external validation using the ACS-NSQIP database.

METHODS

TRIPOD guidelines were followed. A validation cohort was created with the ACS-NSQIP dataset. Risk groups for RBCT were created using the TRS: anemia (hematocrit ≤36%), major liver resection (≥4 segments) and primary liver malignancy. Concordance index was used to assess the discrimination. The Hosmer-Lemeshow test for goodness of fit and calibration curves were used to assess calibration.

RESULTS

Of 2854 hepatectomies, 18.9% received RBCT. The TRS stratified patients from low (8.5% risk of RBCT) to very high risk (40.6%) of RBCT. The concordance was 0.68 (95% CI 0.66-0.70). Hosmer-Lemeshow test and calibration curves supported good predictive performance of the model.

CONCLUSION

The TRS adequately discriminated risk of RBCT in an external sample of patients undergoing hepatectomy. It provides a simple method to identify patients at high transfusion risk. It can be used to tailor patient blood management initiatives and reduce the use of RBCT.

The effectiveness of acute normolvolemic hemodilution and autologous prime on intraoperative blood management during cardiac surgery

Objective:

Intraoperative blood management during cardiac surgery is a multifaceted process incorporating various interventions directed at optimizing oxygen delivery and enhancing hemostasis. The purpose of this study was to evaluate the effects of acute normovolemic hemodilution (ANH) and autologous priming (AP) on preserving the hematocrit during cardiopulmonary bypass (CPB).

Method:

Case records from a national registry of adult patients who underwent cardiac surgery between January and October 2016 were reviewed. Groups were determined as follows: ANH, AP, ANH+AP or Neither. Primary endpoint was first the hematocrit on CPB with secondary endpoints of hematocrit drift and red blood cell (RBC) transfusion rate.

Results:

Eighteen thousand and twenty-four (18,024) consecutive patients were reviewed. The first CPB hematocrit was lowest in the ANH group (26.5%±4.4%) and highest in ANH+AP patients (27.5%±4.8%) (p<0.001). The change in hematocrit was greatest in the ANH group (8.3%±3.9%) compared to both the AP (6.4%±3.8%) and ANH+AP (6.9%±4.1%) groups (p<0.001). Intraoperative RBC transfusions were as follows: ANH 26 (7.8%), AP 2,531 (20.0%), ANH+AP 287 (10.3%) and Neither 592 (26.7%) (p<0.001).

Conclusions:

Regression results show that the use of ANH will result in the greatest decline in hematocrit values. When combined with AP, higher hematocrits and lower transfusions were seen.

Three-point transfusion risk score in hepatectomy

BACKGROUND

Perioperative red blood cell transfusions are required in up to 23 per cent of patients undergoing hepatectomy. Previous research has developed three transfusion risk scores to assess risk of perioperative red blood cell transfusion. Here, the performance of these transfusion risk scores was evaluated in a multicentre cohort of patients who underwent hepatectomy and compared with that of a simplified transfusion risk score.

METHODS

A database of patients undergoing hepatectomy at four specialized centres between 2008 and 2012 was developed. External validity was assessed by discrimination and calibration. Discrimination was evaluated using the area under the receiver operating characteristic (ROC) curve (AUC). Calibration was evaluated by the degree of agreement between predicted and actual red blood cell transfusion probabilities. A simplified transfusion risk score using variables common to the three models was created, and discrimination and calibration were evaluated.

RESULTS

There were 1287 patients included in this study, with 341 (26·5 per cent) receiving a red blood cell transfusion. Discriminative ability was similar between the three transfusion risk scores, with AUCs of 0·66-0·68 and good calibration. A new three-point risk score was developed based on factors present in all models: haemoglobin 12·5 g/dl or less, primary liver malignancy and major resection (at least 4 segments). Discriminative ability and calibration of the three-point model were similar to those of the three existing models, with an AUC of 0·66.

CONCLUSION

The three-point transfusion risk score simplifies assessment of perioperative transfusion risk in hepatectomy without sacrificing predictive ability.

Methods to decrease blood loss during liver resection: a network meta-analysis

BACKGROUND

Liver resection is a major surgery with significant mortality and morbidity. Specialists have tested various methods in attempts to limit blood loss, transfusion requirements, and morbidity during elective liver resection. These methods include different approaches (anterior versus conventional approach), use of autologous blood donation, cardiopulmonary interventions such as hypoventilation, low central venous pressure, different methods of parenchymal transection, different methods of management of the raw surface of the liver, different methods of vascular occlusion, and different pharmacological interventions. A surgeon typically uses only one of the methods from each of these seven categories. The optimal method to decrease blood loss and transfusion requirements in people undergoing liver resection is unknown.

OBJECTIVES

To assess the effects of different interventions for decreasing blood loss and blood transfusion requirements during elective liver resection.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, and Science Citation Index Expanded to September 2015 to identify randomised clinical trials. We also searched trial registers and handsearched the references lists of identified trials.

SELECTION CRITERIA

We included only randomised clinical trials (irrespective of language, blinding, or publication status) comparing different methods of decreasing blood loss and blood transfusion requirements in people undergoing liver resection.

DATA COLLECTION AND ANALYSIS

Two review authors independently identified trials and collected data. We assessed the risk of bias using Cochrane domains. We conducted a Bayesian network meta-analysis using the Markov chain Monte Carlo method in WinBUGS 1.4, following the guidelines of the National Institute for Health and Care Excellence Decision Support Unit guidance documents. We calculated the odds ratios (OR) with 95% credible intervals (CrI) for the binary outcomes, mean differences (MD) with 95% CrI for continuous outcomes, and rate ratios with 95% CrI for count outcomes, using a fixed-effect model or random-effects model according to model-fit. We assessed the evidence with GRADE.

MAIN RESULTS

We identified 67 randomised clinical trials involving a total of 6197 participants. All the trials were at high risk of bias. A total of 5771 participants from 64 trials provided data for one or more outcomes included in this review. There was no evidence of differences in most of the comparisons, and where there was, these differences were in single trials, mostly of small sample size. We summarise only the evidence that was available in more than one trial below. Of the primary outcomes, the only one with evidence of a difference from more than one trial under the pair-wise comparison was in the number of adverse events (complications), which was higher with radiofrequency dissecting sealer than with the clamp-crush method (rate ratio 1.85, 95% CrI 1.07 to 3.26; 250 participants; 3 studies; very low-quality evidence). Among the secondary outcomes, the only differences we found from more than one trial under the pair-wise comparison were the following: blood transfusion (proportion) was higher in the low central venous pressure group than in the acute normovolemic haemodilution plus low central venous pressure group (OR 3.19, 95% CrI 1.56 to 6.95; 208 participants; 2 studies; low-quality evidence); blood transfusion quantity (red blood cells) was lower in the fibrin sealant group than in the control (MD -0.53 units, 95% CrI -1.00 to -0.07; 122 participants; 2; very low-quality evidence); blood transfusion quantity (fresh frozen plasma) was higher in the oxidised cellulose group than in the fibrin sealant group (MD 0.53 units, 95% CrI 0.36 to 0.71; 80 participants; 2 studies; very low-quality evidence); blood loss (MD -0.34 L, 95% CrI -0.46 to -0.22; 237 participants; 4 studies; very low-quality evidence), total hospital stay (MD -2.42 days, 95% CrI -3.91 to -0.94; 197 participants; 3 studies; very low-quality evidence), and operating time (MD -15.32 minutes, 95% CrI -29.03 to -1.69; 192 participants; 4 studies; very low-quality evidence) were lower with low central venous pressure than with control. For the other comparisons, the evidence for difference was either based on single small trials or there was no evidence of differences. None of the trials reported health-related quality of life or time needed to return to work.

AUTHORS' CONCLUSIONS

Paucity of data meant that we could not assess transitivity assumptions and inconsistency for most analyses. When direct and indirect comparisons were available, network meta-analysis provided additional effect estimates for comparisons where there were no direct comparisons. However, the paucity of data decreases the confidence in the results of the network meta-analysis. Low-quality evidence suggests that liver resection using a radiofrequency dissecting sealer may be associated with more adverse events than with the clamp-crush method. Low-quality evidence also suggests that the proportion of people requiring a blood transfusion is higher with low central venous pressure than with acute normovolemic haemodilution plus low central venous pressure; very low-quality evidence suggests that blood transfusion quantity (red blood cells) was lower with fibrin sealant than control; blood transfusion quantity (fresh frozen plasma) was higher with oxidised cellulose than with fibrin sealant; and blood loss, total hospital stay, and operating time were lower with low central venous pressure than with control. There is no evidence to suggest that using special equipment for liver resection is of any benefit in decreasing the mortality, morbidity, or blood transfusion requirements (very low-quality evidence). Radiofrequency dissecting sealer should not be used outside the clinical trial setting since there is low-quality evidence for increased harm without any evidence of benefits. In addition, it should be noted that the sample size was small and the credible intervals were wide, and we cannot rule out considerable benefit or harm with a specific method of liver resection.

Anesthetic and operative considerations for laparoscopic liver resection

We enumerate the broad range of anesthetic considerations that affect the outcome of patients undergoing laparoscopic liver resection. Key elements for excellent outcomes after laparoscopic liver resection are careful patient selection and risk stratification, appropriate monitoring, techniques to reduce blood loss and transfusion, and active recovery management. Although some of these key elements are the same for open liver operation, there are specific anesthetic considerations of which both the surgical and anesthesia teams must be aware to achieve optimal patient outcomes after laparoscopic liver resection. While unique advantages of laparoscopic liver resection typically include decreased intraoperative bleeding, transfusion requirements, and a lower incidence of postoperative ascites, specific challenges include management of the complicated interplay between low-volume anesthesia and increased intraabdominal pressure due to pneumoperitoneum, with additional considerations regarding circulatory support to treat acute blood loss with need for emergent conversion in some cases. This article will address in detail the preoperative, intraoperative, and postoperative anesthetic considerations for patients undergoing laparoscopic liver resection that both the surgical and anesthesia team should be aware of to optimize outcomes.

A novel approach to modeling acute normovolemic hemodilution

Acute normovolemic hemodilution (ANH) was introduced as a blood conservation technique to reduce patient exposure to allogenic blood transfusion during surgery. Despite years of research and experience, the best practice procedure, efficacy and safety of ANH remain in question. In this work, a numerical model is developed for the ANH procedure based upon a multi-compartmental, fluid model of the body. The model also analyzes the most commonly used acellular fluids for ANH or for fluid therapy following hemorrhage. The model allows user input of critical ANH parameters, providing the ability to simulate the patient׳s response in real time to many clinical scenarios, using various types of resuscitation fluids. First, the patient׳s response to a representative, clinical ANH protocol and surgery was simulated. Then, the effect of several variables was investigated including: type/amount of resuscitation fluid, number of blood units collected during ANH, and amount of surgical blood loss. Our simulations highlighted the importance of osmotic molecules within the blood in preventing excessive fluid retention and initiating fluid clearance after surgery. The developed model can be utilized as a tool to simulate and optimize a variety of proposed protocol related to the ANH procedure and surgery. It can also be utilized as an educational or training tool to become familiar with the ANH procedure.

Anaesthetic and pharmacological techniques to decrease blood loss in liver surgery: a systematic review

BACKGROUND

There is increasing evidence that perioperative blood loss and blood transfusions are associated with poorer short- and long-term outcomes in patients undergoing hepatectomy. The aim of this study was to systematically review the literature for non-surgical measures to decrease intraoperative blood loss during liver surgery.

METHODS

The literature search was performed using PubMed, Embase, Cochrane Library, CINAHL and Google Scholar databases. The primary outcome measures were perioperative blood loss and transfusion requirements. A secondary outcome measure was development of ischaemia-reperfusion injury.

RESULTS

Seventeen studies met the inclusion criteria and included 1573 patients. All were randomized controlled studies. In eight studies (n = 894), pharmacological methods, and in another nine studies (n = 679), anaesthetic methods to decrease blood loss were investigated. Anti-fibrinolytic drugs, acute normovolaemic haemodilution, autologous blood donation and use of inhalational anaesthetic agent may affect blood loss and post-operative hepatic function.

CONCLUSIONS

There is potential for use of non-surgical techniques to decrease perioperative bleeding. However, on the basis of this review alone, due to heterogeneity of randomized trials conducted, no particular strategy can be recommended. Future studies should be conducted looking at pathways to decrease bleeding in liver surgery.

Practice guidelines for perioperative blood management: an updated report by the American Society of Anesthesiologists Task Force on Perioperative Blood Management*

The American Society of Anesthesiologists Committee on Standards and Practice Parameters and the Task Force on Perioperative Blood Management presents an updated report of the Practice Guidelines for Perioperative Blood Management.

Supplemental Digital Content is available in the text.

The accuracy of non-invasively continuous total hemoglobin measurement by pulse CO-Oximetry undergoing acute normovolemic hemodilution and reinfusion of autologous blood

BACKGROUND

Non-invasively continuous total hemoglobin (SpHb) measurement has not been assessed adequately in acute bleeding and rapid blood transfusion during surgery. Thus, we have assessed the efficacy of SpHb during both acute normovolemic hemodilution (ANH) and autologous blood transfusion (ABT).

METHODS

Twenty-four patients undergoing urological and gynecological surgery were enrolled. ANH was induced by withdrawing blood of 800 g with simultaneous fluid administration. When surgical hemostasis was completed, collected blood was reinfused. Measurement of SpHb, perfusion index (PI) and real total Hb (tHb) were done before and after each 400 ml blood removal (-0, -400, -800 ml) and reinfusion (+0, +400, +800 ml).

RESULTS

A Bland-Altman analysis for repeated measurements showed a bias (precision) g/dl of 1.12 (1.25), 1.43 (1.24) and 1.10 (1.23) for all data, during ANH and during ABT, respectively. Additionally, a bias (precision) increased with a reduction in tHb (g/dl): ≥10.0; 0.74 (1.30), 8.0-10.0; 1.15 (1.12) and <8.0; 1.60 (1.28). Although the difference between SpHb and tHb was almost zero before anesthesia induction, it became significant just before ANH and did not change further by ANH and ABT. Significant correlations between SpHb and tHb for all data (r = 0.75, n = 228, p < 0.001) were observed. PI slightly correlated with the difference between SpHb and tHb (r = 0.38, n = 216, p < 0.001). Furthermore, before and after induction of anesthesia, PI also correlated with the difference between SpHb and tHb (r = 0.42, n = 23, p = 0.048 and r = 0.51, n = 22, p = 0.016, respectively).

CONCLUSIONS

The present data suggest that SpHb may overestimate tHb during ANH and ABT. In addition, PI and tHb levels had an impact on the accuracy of SpHb measurements.

Methods to decrease blood loss during liver resection: a network meta-analysis

BACKGROUND

Liver resection is a major surgery with significant mortality and morbidity. Various methods have been attempted to decrease blood loss and morbidity during elective liver resection. These methods include different methods of vascular occlusion, parenchymal transection, and management of the cut surface of the liver. A surgeon typically uses only one of the methods from each of these three categories. Together, one can consider this combination as a treatment strategy. The optimal treatment strategy for liver resection is unknown.

OBJECTIVES

To assess the comparative benefits and harms of different treatment strategies that aim to decrease blood loss during elective liver resection.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, and Science Citation Index Expanded to July 2012 to identify randomised clinical trials. We also handsearched the references lists of identified trials.

SELECTION CRITERIA

We included only randomised clinical trials (irrespective of language, blinding, or publication status) where the method of vascular occlusion, parenchymal transection, and management of the cut surface were clearly reported, and where people were randomly assigned to different treatment strategies based on different combinations of the three categories (vascular occlusion, parenchymal transection, cut surface).

DATA COLLECTION AND ANALYSIS

Two review authors identified trials and collected data independently. We assessed the risk of bias using The Cochrane Collaboration's methodology. We conducted a Bayesian network meta-analysis using the Markov chain Monte Carlo method in WinBUGS 1.4 following the guidelines of the National Institute for Health and Care Excellence Decision Support Unit guidance documents. We calculated the odds ratios (OR) with 95% credible intervals (CrI) (which are similar to confidence intervals in the frequentist approach for meta-analysis) for the binary outcomes and mean differences (MD) with 95% CrI for continuous outcomes using a fixed-effect model or random-effects model according to model-fit.

MAIN RESULTS

We identified nine trials with 617 participants that met our inclusion criteria. Interventions in the trials included three different options for vascular occlusion, four for parenchymal transection, and two for management of the cut liver surface. These interventions were combined in different ways in the trials giving 11 different treatment strategies. However, we were only able to include 496 participants randomised to seven different treatment strategies from seven trials in our network meta-analysis, because the treatment strategies from the trials that used fibrin sealant for management of the raw liver surface could not be connected to the network for any outcomes. Thus, the trials included in the network meta-analysis varied only in their approaches to vascular exclusion and parenchymal transection and none used fibrin sealant. All the trials were of high risk of bias and the quality of evidence was very low for all the outcomes. The differences in mortality between the different strategies was imprecise (seven trials; seven treatment strategies; 496 participants). Five trials (six strategies; 406 participants) reported serious adverse events. There was an increase in the proportion of people with serious adverse events when surgery was performed using radiofrequency dissecting sealer compared with the standard clamp-crush method in the absence of vascular occlusion and fibrin sealant. The OR for the difference in proportion was 7.13 (95% CrI 1.77 to 28.65; 15/49 (adjusted proportion 24.9%) in radiofrequency dissecting sealer group compared with 6/89 (6.7%) in the clamp-crush method). The differences in serious adverse events between the other groups were imprecise. There was a high probability that 'no vascular occlusion with clamp-crush method and no fibrin' and 'intermittent vascular occlusion with Cavitron ultrasonic surgical aspirator and no fibrin' are better than other treatments with regards to serious adverse events. Quality of life was not reported in any of the trials.The differences in the proportion of people requiring blood transfusion was imprecise (six trials; seven treatments; 446 participants). Two trials (three treatments; 155 participants) provided data for quantity of blood transfused. People undergoing liver resection by intermittent vascular occlusion had higher amounts of blood transfused than people with continuous vascular occlusion when the parenchymal transection was carried out with the clamp-crush method and no fibrin sealant was used for the cut surface (MD 1.2 units; 95% CrI 0.08 to 2.32). The differences in the other comparisons were imprecise (very low quality evidence). Three trials (four treatments; 281 participants) provided data for operative blood loss. People undergoing liver resection using continuous vascular occlusion had lower blood loss than people with no vascular occlusion when the parenchymal transection was carried out with clamp-crush method and no fibrin sealant was used for the cut surface (MD -130.9 mL; 95% CrI -255.9 to -5.9). None of the trials reported the proportion of people with major blood loss.The differences in the length of hospital stay (six trials; seven treatments; 446 participants) and intensive therapy unit stay (four trials; six treatments; 261 participants) were imprecise. Four trials (four treatments; 245 participants) provided data for operating time. Liver resection by intermittent vascular occlusion took longer than liver resection performed with no vascular occlusion when the parenchymal transection was carried out with Cavitron ultrasonic surgical aspirator and no fibrin sealant was used for the cut surface (MD 49.6 minutes; 95% CrI 29.8 to 69.4). The differences in the operating time between the other comparisons were imprecise. None of the trials reported the time needed to return to work.

AUTHORS' CONCLUSIONS

Very low quality evidence suggested that liver resection using a radiofrequency dissecting sealer without vascular occlusion or fibrin sealant may increase serious adverse events and this should be evaluated in further randomised clinical trials. The risk of serious adverse events with liver resection using no special equipment compared with more complex methods requiring special equipment was uncertain due to the very low quality of the evidence. The credible intervals were wide and considerable benefit or harm with a specific method of liver resection cannot be ruled out.

Stationary versus agitated storage of whole blood during acute normovolemic hemodilution

BACKGROUND

Acute normovolemic hemodilution is an intraoperative technique to reduce the number of red blood cells lost in shed blood during surgery. Standard guidelines for storage of platelets recommend constant gentle agitation to maintain gas exchange for the metabolically active platelets. The collected whole blood (WB) for acute normovolemic hemodilution remains stationary for as long as 8 hours before reinfusion. We hypothesized that gentle agitation of WB throughout storage would improve the coagulation properties of the WB at the time of reinfusion.

METHODS

WB was collected from 10 volunteer donors and control samples taken. The units were split in 2 storage groups: agitated (rocked) and stationary (unrocked). Cell counts and fibrinogen levels, as well as thromboelastography (TEG®) measurements, including TEG® PlateletMapping® assays, were performed on the control sample and the test samples after 8 hours of rocked or unrocked storage at room temperature.

RESULTS

Nine units WB from 9 different healthy volunteers were tested. There were no significant differences in hematocrit, hemoglobin, red blood cells counts, platelet counts, or fibrinogen levels between the control samples and the rocked and unrocked WB samples. WB coagulation as measured by TEG® was preserved during the 8-hour storage period in both the rocked and unrocked samples. There were no significant differences between the control, rocked, and unrocked samples in time to initiate clotting, time of clot formation, rate of clot formation, or maximum strength of clot values. There were also no significant differences in the fibrin contribution to clot strength between the control, rocked, and unrocked samples, and no significant difference between the platelet activation from adenosine diphosphate or arachidonic acid among any of the 3 groups.

CONCLUSIONS

Given the small sample size, there is no statistical evidence on which to reject the null hypothesis of there being no difference in the changes from the baseline between coagulation function as measured by TEG® between WB that is either agitated or kept stationary for 8 hours. These findings need to be confirmed in a larger study.

Blood conservation strategies in orthopedic surgeries: A review

In orthopedics management of surgical blood loss is an important aspect which has evolved along with modern surgeries. Replacement of lost blood by transfusion alone is not the answer as was considered earlier. Complications like infection and immune reaction due to blood transfusion are a major concern. Today numerous techniques are available in place of allogenic blood transfusion which can be employed safely and effectively. In this article we have reviewed these techniques, their merits and demerits.

Minimizing blood loss during hepatectomy: a literature review

There are numerous techniques surgeons employ to reduce blood loss during partial hepatectomy. In this literature review, prospective studies from the last 20 years are examined to determine the techniques that are best supported by the literature. Some of the techniques include vascular control, multiple parenchymal transection techniques, various hemostatic agents, low central venous pressure, and hemodilution. The strategies supported most convincingly by the literature include low CVP and total hepatic inflow occlusion.

Blood utilization: fostering an effective hospital transfusion culture

An effective hospital transfusion culture should encourage clinicians to consider the possibility of transfusion in their patients well before the need actually arises, and to plan ahead in an attempt to use blood products most efficiently. Strategies for improved blood utilization include timely and adequate preoperative assessment of risk, optimization of baseline hemoglobin, anticipation of potential transfusion problems, intraoperative techniques to minimize blood loss, blood conservation technologies, transfusion guidelines and targeted therapy, point of care testing, and massive transfusion protocols. Attention to these elements promotes a safe and cost-effective transfusion culture.

Cardiopulmonary interventions to decrease blood loss and blood transfusion requirements for liver resection

BACKGROUND

Blood loss during liver resection is considered one of the most important factors affecting the peri-operative outcomes of patients undergoing liver resection.

OBJECTIVES

To determine the benefits and harms of cardiopulmonary interventions to decrease blood loss and to decrease allogeneic blood transfusion requirements in patients undergoing liver resections.

SEARCH METHODS

We searched the Cochrane Hepato-Biliary Group Controlled Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library, MEDLINE, EMBASE, and Science Citation Index Expanded until January 2012 to identify randomised trials.

SELECTION CRITERIA

We included all randomised clinical trials comparing various cardiopulmonary interventions aimed at decreasing blood loss and allogeneic blood transfusion requirements in patients undergoing liver resection. Trials were included irrespective of whether they included major or minor liver resections of normal or cirrhotic livers, vascular occlusion was used or not, and irrespective of the reason for liver resection.

DATA COLLECTION AND ANALYSIS

Two authors independently identified trials for inclusion and independently extracted data. We analysed the data with both the fixed-effect and the random-effects models using RevMan Analysis. For each outcome we calculated the risk ratio (RR), mean difference (MD), or standardised mean difference (SMD) with 95% confidence intervals (CI) based on intention-to-treat analysis or available case analysis. For dichotomous outcomes with only one trial included under the outcome, we performed the Fisher's exact test.

MAIN RESULTS

Ten trials involving 617 patients satisfied the inclusion criteria. The interventions included low central venous pressure (CVP), autologous blood donation, haemodilution, haemodilution with controlled hypotension, and hypoventilation. Only one or two trials were included under most comparisons. All trials had a high risk of bias. There was no significant difference in the peri-operative mortality in any of the comparisons: low CVP versus no intervention (3 trials, 0/88 (0%) patients in the low CVP group versus 1/89 (1.1%) patients in the no intervention group); autologous blood donation versus no intervention (1 trial, 0/40 (0%) versus 0/39 (0%)); haemodilution versus no intervention (2 trials, 1/73 (1.4%) versus 3/77 (3.9%) in one of these trials); haemodilution with controlled hypotension versus no intervention (1 trial, 0/10 (0%) versus 0/10 (0%)); haemodilution with bovine haemoglobin (HBOC-201) versus haemodilution with hydroxy ethyl starch (HES) (1 trial, 1/6 (16.7%) versus 0/6 (0%)); hypoventilation versus no intervention (1 trial, 0/40 (0%) versus 0/39 (0%)). None of the trials reported long-term survival or quality of life. The risk ratio of requiring allogeneic blood transfusion was significantly lower in the haemodilution versus no intervention groups (3 trials, 16/115 (weighted proportion = 14.2%) versus 41/118 (34.7%), RR 0.41 (95% CI 0.25 to 0.66), P = 0.0003); and for haemodilution with controlled hypotension versus no intervention (1 trial, 0/10 (0%) versus 10/10 (100%), P < 0.0001). There were no significant differences in the allogeneic transfusion requirements in the other comparisons which reported this outcome, such as low CVP versus no intervention, autologous blood donation versus control, and hypoventilation versus no intervention.

AUTHORS' CONCLUSIONS

None of the interventions seemed to decrease peri-operative morbidity or offer any long-term survival benefit. Haemodilution shows promise in the reduction of blood transfusion requirements in liver resection surgery. However, there is a high risk of type I (erroneously concluding that an intervention is beneficial when it is actually not beneficial) and type II errors (erroneously concluding that an intervention is not beneficial when it is actually beneficial) because of the few trials included, the small sample size in each trial, and the high risk of bias in the trials. Further randomised clinical trials with low risk of bias and random errors that assess clinically important outcomes such as peri-operative mortality are necessary to assess any cardiopulmonary interventions aimed at decreasing blood loss and blood transfusion requirements in patients undergoing liver resections. Trials need to be designed to assess the effect of a combination of different interventions in liver resections.

Preoperative autologous blood donation and acute normovolemic hemodilution affect intraoperative blood loss during sagittal split ramus osteotomy

INTRODUCTION

This study aimed to determine the effects of acute normovolemic hemodilution (ANH) using low-molecular-weight hydroxyethyl starch (LMW-HES) on intraoperative blood loss in patients who had received preoperative autologous blood donation (PABD) and had undergone sagittal split ramus osteotomy (SSRO).

METHODS

Patients who had undergone SSRO were analyzed. All 250 patients received PABD of 400-800 mL until 2 weeks before surgery. ANH was performed by withdrawing whole blood, which was replaced by the same volume of LMW-HES. ANH was performed in 197 cases for 200 mL replacement (ANH-200) and in 5 cases for 400 mL replacement (ANH-400); it was not performed in 48 cases (ANH-0).

RESULTS

Blood loss in ANH-200 was greater than that in ANH-0, despite no differences in hemoglobin concentrations at pre- and post-PABD, prothrombin time, activated partial thromboplastin time, fibrinogen and platelet counts between the groups before surgery. Blood loss increased as the total withdrawn blood (sum of PABD and ANH) increased.

CONCLUSION

Increased intraoperative blood loss was associated with total withdrawn blood before the operation as well as ANH.

[Anesthesiology: partner or competitor?]

Surgery and anesthesiology have always been closely connected. Within the increasing complexity of therapies and technical capabilities both subjects overlap in certain areas. This article deals with the question whether anesthesiology is acting as a partner or competitor in the cooperation with the various operative specialties. In several studies it has been shown that the outcome of surgical patients can be improved by communication and interaction with anesthesiology and that forming multidisciplinary teams will be highly beneficial for patients in intensive care units.

Relationship between intraoperative fluid administration and perioperative outcome after pancreaticoduodenectomy: results of a prospective randomized trial of acute normovolemic hemodilution compared with standard intraoperative management

BACKGROUND

Pancreaticoduodenectomy (PD) can be associated with significant blood loss and transfusion requirements, with potential adverse short- and long-term consequences. The aim of this study was to determine whether acute normovolemic hemodilution (ANH), an established blood conservation technique, reduces perioperative allogeneic transfusions in patients undergoing PD.

METHODS

One hundred thirty patients undergoing PD were randomized to ANH or standard management (STDM). In the ANH group, intraoperative blood collection was performed to a target hemoglobin of 8.0 g/dL; crystalloid and colloid were used for volume replacement. Strict transfusion triggers were applied during and after operation. Perioperative complications were prospectively assessed and graded for severity.

RESULTS

From July 2005 to May 2009, 209 patients were registered, 79 excluded, 65 were randomized to ANH, and 65 to STD. The groups were well matched for demographic, operative, and histopathologic variables. Patients undergoing ANH received over 2 L more fluid intraoperatively (6250 mL, range 2000-11850) compared with patients undergoing STD (3900 mL, range 2000-9000) (P < 0.001). Transfusion rates were similar (ANH = 16.9%, 30 units vs STD = 18.5%, 33 units; P = 0.82), as was overall perioperative morbidity (ANH = 49.2% vs STD = 47%, P = 0.86). There was, however, a trend toward more grade-3 complications in patients undergoing ANH (32% vs 23.1% STD, P = 0.17), and complications related to the pancreatic anastomosis (leak/fistula/abscess) were significantly higher in the ANH group (21.5% vs 7.7%, P = 0.045). The intraoperative fluid volume was higher for all patients with pancreatic anastomotic complications (n = 19), regardless of randomization arm (ANH 6000 mL, range 2800-11350 mL vs STD 5000 mL, range 2000-11850 mL, P < 0.042).

CONCLUSION

In this randomized trial of patients undergoing PD, ANH did not reduce allogeneic transfusions and resulted in more pancreatic anastomotic complications, likely related to greater intraoperative fluid administration. The benefits of ANH do not necessarily extend to all procedures, and restrictive intravenous fluid management during PD may help improve postoperative outcome.

Alternative procedures for reducing allogeneic blood transfusion in elective orthopedic surgery

Perioperative blood loss is a major problem in elective orthopedic surgery. Allogeneic transfusion is the standard treatment for perioperative blood loss resulting in low postoperative hemoglobin, but it has a number of well-recognized risks, complications, and costs. Alternatives to allogeneic blood transfusion include preoperative autologous donation and intraoperative salvage with postoperative autotransfusion. Orthopedic surgeons are often unaware of the different pre- and intraoperative possibilities of reducing blood loss and leave the management of coagulation and use of blood products completely to the anesthesiologists. The goal of this review is to compare alternatives to allogeneic blood transfusion from an orthopedic and anesthesia point of view focusing on estimated costs and acceptance by both parties.

Perioperative blood conservation

This review examines the science and methodology of blood conservation in modern anaesthetic and surgical practice. Blood transfusion is associated with increased morbidity and mortality in all surgical patients, and the reduction or even elimination of transfusion has been and continues to be the subject of much research. Blood substitutes, despite extensive investigation, have not been proved successful in trials to date, and none have entered clinical practice. Pharmacological treatments include antifibrinolytic drugs (although aprotinin is no longer in clinical use), recombinant factor VIIa, desmopressin, erythropoietin and topical haemostatic agents, and the role of each of these is discussed. Autologous blood transfusion has recently fallen in popularity; however, cell salvage is almost ubiquitous in its use throughout Europe. Anaesthetic and surgical techniques may also be refined to improve blood conservation. Blood transfusion guidelines and protocols are strongly recommended, and repetitive audit and education are instrumental in reducing blood transfusion.

Cardiopulmonary interventions to decrease blood loss and blood transfusion requirements for liver resection

BACKGROUND

Blood loss during liver resection is one of the most important factors affecting the peri-operative outcomes of patients undergoing liver resection.

OBJECTIVES

To determine the benefits and harms of cardiopulmonary interventions to decrease blood loss and to decrease allogeneic blood transfusion requirements in patients undergoing liver resections.

SEARCH STRATEGY

We searched The Cochrane Hepato-Biliary Group Controlled Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library, MEDLINE, EMBASE, and Science Citation Index Expanded until November 2008 for identifying the randomised trials.

SELECTION CRITERIA

We included all randomised clinical trials comparing various cardiopulmonary interventions aimed at decreasing blood loss and allogeneic blood transfusion requirements in liver resection. Trials were included irrespective of whether they included major or minor liver resections, normal or cirrhotic livers, vascular occlusion was used or not, and irrespective of the reason for liver resection.

DATA COLLECTION AND ANALYSIS

Two authors independently identified trials for inclusion and independently extracted data. We analysed the data with both the fixed-effect and the random-effects models using RevMan Analysis. For each outcome we calculated the risk ratio (RR), mean difference (MD), or standardised mean difference (SMD) with 95% confidence intervals (CI) based on intention-to-treat analysis or available case-analysis. For dichotomous outcomes with only one trial included under the outcome, we performed the Fisher's exact test.

MAIN RESULTS

Nine trials involving 587 patients satisfied the inclusion criteria. The interventions included low central venous pressure (CVP), autologous blood donation, haemodilution, haemodilution with controlled hypotension, and hypoventilation. Only one or two trials were included under most comparisons. All trials had a high risk of bias. There was no significant difference in the peri-operative mortality or other peri-operative morbidity. None of the trials reported long-term survival or liver failure.The risk ratio of requiring allogeneic blood transfusion was significantly lower in the haemodilution and haemodilution with controlled hypotension groups than the respective control groups. Other interventions did not show significant decreases of allogeneic transfusion requirements.

AUTHORS' CONCLUSIONS

None of the interventions seem to decrease peri-operative morbidity or offer any long-term survival benefit. Haemodilution shows promise in the reduction of blood transfusion requirements in liver resection surgery. However, there is a high risk of type I (erroneously concluding that an intervention is beneficial when it is actually not beneficial) and type II errors (erroneously concluding that an intervention is not beneficial when it is actually beneficial) because of the few trials included, the small sample size in each trial, and the high risk of bias. Further randomised clinical trials with low risk of bias and random errors assessing clinically important outcomes such as peri-operative mortality are necessary to assess any cardiopulmonary interventions aimed at decreasing blood loss and blood transfusion requirements in liver resections. Trials need to be designed to assess the effect of a combination of different interventions in liver resections.

The effect of hemodilution during normothermic cardiac surgery on renal physiology and function: a review

Although the definitions of renal dysfunction vary, loss of renal function is a common complication following cardiac surgery using cardiopulmonary bypass (CPB). When postoperative dialysis is required, mortality is approximately 50%. CPB-accompanied hemodilution is a major contributing factor to renal damage as it notably reduces oxygen delivery by reducing the oxygen transport capacity of the blood as well as disturbing the microcirculation. To minimize hypoxemic damage during CPB, lowering of body temperature is applied to reduce the patient’s metabolic rate. At present, however, temperature management during elective adult cardiac surgery is shifting from moderate hypothermia to normothermia. To determine whether the currently accepted levels of hemodilution during CPB can suffice the normothermic patient’s high oxygen demand, we focused this study on renal physiology and postoperative renal function. Hemodilution reduces the capillary density through a diminished capillary viscosity, thereby, redistributing blood from the renal medulla to the renal cortex. As the physiology of the renal medulla makes it a hypoxic environment, this part of the kidney appears to be especially at risk for hypoxic damage caused by a hemodilution-induced lowered oxygen transport and oxygen delivery. In addition, hemodilution is also likely to disturb the hormonal systems regulating renal blood distribution. Clinical studies, mostly of retrospective or observational nature, show that perioperative nadir hematocrit levels lower than approximately 24% are associated with an increased risk to develop postoperative renal failure. A better comprehension of the cause-and-effect relation between low perioperative hematocrits and loss of postoperative renal function may enable more effective renal protective strategies.

Perioperative anemia in the elderly

Anemia is characterized by less than the normal number of red blood cells (RBCs) (as a result of underproduction, increased loss, or destruction) or decreased quantity of hemoglobin (Hgb) in the blood, thereby reducing the blood's oxygen-carrying capacity.